Experimental evidence for trapped exciton states in liquid rare gases

1970 ◽  
Vol 317 (1528) ◽  
pp. 113-131 ◽  
Keyword(s):  
Experimental Evidence ◽  
Absorption Spectra ◽  
Disordered Systems ◽  
Vacuum Ultraviolet ◽  
Solid Phase ◽  
Liquid System ◽  
Rare Gases ◽  
Line Broadening ◽  
Absorption Bands ◽  
Additional Line

In connexion with studies of the electronic structure of disordered systems, we enquire whether there exist exciton states in simple liquids. We report the results of a vacuum ultraviolet spectroscopic study of liquid argon and of liquid krypton doped with xenon. Experimental evidence was obtained for Wannier-Mott type impurity states in liquids which have no parentage in the excited states of the isolated atoms constituting the dense fluid. The absorption spectra of the doped liquid rare gases were monitored in the region 160 to 120 nm. The following experimental results are reported: (a) In the Xe/Ar liquid two absorption bands corresponding to the 1 S 0 → 3 P 1 and to the 1 S 0 → 1 P 1 transitions (or alternatively to the n = 1 Wannier states) were identified at 141 nm (8.80eV)† and at 123nm (10.1 eV). An additional line was observed at 127 nm (9.76eV). (b) In the Xe/Kr liquid three absorption bands were observed at 144.5 nm (8.59 eV), 125.5 nm (9.89 eV) and 129 nm (9.6 eV). (c) The absorption spectra of the doped liquids were compared with the spectra of 1 cm thick doped solid rare-gas crystals. From these results we conclude that: (a) The 127 nm (9.76 eV) band in the Xe/Ar liquid system and the 129 nm (9.61 eV) band in the Xe/Kr liquid system cannot be attributed to a perturbed ‘atomic’ state and are assigned to the n = 2 Wannier state in the liquid. (b) Line broadening of exciton states in the liquid can be accounted for by a simple scattering model. (c) Preliminary information on band gaps in liquid rare gases were obtained from the spectroscopic data. (d) The effect of liquid-solid phase transition on the line broadening of exciton states is consistent with electron mobility data in these systems.

scholarly journals Terahertz Absorption Spectroscopy of Benzamide, Acrylamide, Caprolactam, Salicylamide, and Sulfanilamide in the Solid State

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ye Jiang ◽  
Fengshan Zhou ◽  
Xiaodong Wen ◽  
Limin Yang ◽  
Guozhong Zhao ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Absorption Spectra ◽  
Density Functional ◽  
Room Temperature ◽  
Solid Phase ◽  
Absorption Bands ◽  
Functional Theory ◽  
Terahertz Absorption ◽  
Thz Absorption

Terahertz (THz) absorption spectra of the similarly structured molecules with amide groups including benzamide, acrylamide, caprolactam, salicylamide, and sulfanilamide in the solid phase at room temperature and 7.8 K for salicylamide are reported and compared to infrared vibrational spectral calculations using density functional theory. The results of THz absorption spectra show that the molecules have characteristic bands in the region of 0.2–2.6 THz (~7–87 cm−1). THz technique can be used to distinguish different molecules with amide groups. In the THz region benzamide has three bands at 0.83, 1.63, and 1.73 THz; the bands are located at 1.44 and 2.00 THz for acrylamide; the bands at 1.24, 1.66 and 2.12 THz are observed for caprolactam. The absorption bands are located at 1.44, 1.63, and 2.39 THz at room temperature, and at 1.22, 1.46, 1.66, and 2.41 THz at low temperature for salicylamide. The bands at 1.63, 1.78, 2.00, and 2.20 THz appear for sulfanilamide. These bands in the THz region may be related to torsion, rocking, wagging, and other modes of different groups in the molecules.

The photoabsorption of chlorodifluoroethenes in the vacuum ultraviolet

1985 ◽  
Vol 63 (7) ◽  
pp. 1949-1954 ◽  
Author(s):  
Eckart Rühl ◽  
Hans-Werner Jochims ◽  
Helmut Baumgärtel
Keyword(s):  
Energy Range ◽  
Ionization Potential ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Photon Energy ◽  
Vacuum Ultraviolet ◽  
Rydberg Series ◽  
Absorption Bands ◽  
Broad Absorption ◽  
Cis And Trans

The gas phase absorption spectra of 2-chloro-1,1-difluoroethene, cis- and trans-1-chloro-1,2-difluoroethene have been measured in the photon energy range from 6.5 to 25 eV. The π → π* transition is assigned to bands centered around 7.17 – 7.20 eV for all three isomers. Four Rydberg series are observed in all the spectra, converging to the π ionization potential: two np-type Rydberg series, one ns, and one nd series are assigned. The convergence limits are: 9.84 eV (2-chloro-1,1-difluoroethene), 9.86 eV (trans-1-chloro-1,2-difluoroethene), and 9.85 eV (trans-1-chloro-1,2-difluoroethene). In the case of 2-chloro-1,1-difluoroethene four additional Rydberg series are found converging to the nCl ionization potential. The convergence limit of these series is 12.15 eV.Above 12 eV broad absorption bands dominate the spectra.

Absorption spectra of O2 in the a1Δg, , and states

1968 ◽  
Vol 46 (5) ◽  
pp. 337-342 ◽  
Author(s):  
F. Alberti ◽  
R. A. Ashby ◽  
A. E. Douglas
Keyword(s):  
Absorption Spectra ◽  
Ground State ◽  
Vacuum Ultraviolet ◽  
Electronic States ◽  
Ultraviolet Spectrum ◽  
Absorption Bands

A number of new absorption bands have been found in the vacuum ultraviolet spectrum of O2 that has been excited by a discharge. The lower states of these bands are the [Formula: see text] and a1Δg states. The analysis of the bands, together with some newly analyzed bands arising from ground-state O2, has allowed us to identify four new electronic states. It has not been possible to assign these states to particular electron configurations of O2.

VACUUM ULTRAVIOLET ABSORPTION SPECTRA OF SOLID HYDROGEN HALIDES

2002 ◽  
Vol 09 (02) ◽  
pp. 1351-1356
Author(s):  
MAKOTO WATANABE ◽  
KAZUMASA OKADA ◽  
TOSHIO IBUKI
Keyword(s):  
Absorption Spectra ◽  
Structural Transition ◽  
Vacuum Ultraviolet ◽  
Spectral Feature ◽  
Solid Hydrogen ◽  
Frenkel Exciton ◽  
Rare Gases ◽  
Hydrogen Halides ◽  
Deposited Films ◽  
Isolated Molecules

Absorption spectra of solid HCl, HBr and HI films deposited on LiF single crystals cooled at 103–104 K and those annealed have been obtained in the 4–11.5 eV region. The first peaks found around the absorption edges correspond to the first bands (dissociative) in isolated molecules, so that they are regarded as Frenkel exciton peaks. The spectral feature of as-deposited films changed after annealing irreversibly, which suggests the structural transition from an amorphous phase to a crystalline phase in HCl and HBr. In HI, it was revealed that the first band in the gaseous phase consists of three components. The broad structures found above the first peaks do not resemble the structures of the isolated molecules in the same energy region which consist of many lines. The band structures of solid hydrogen halides seem to resemble those of sodium halide crystals and solid rare gases.

Mechanism of anionic coordination dimerization of isoprene

1981 ◽  
Vol 46 (7) ◽  
pp. 1600-1606 ◽  
Author(s):  
Jan Bartoň ◽  
Karel Volka ◽  
Miroslav Kašpar ◽  
Vlastimil Růžička
Keyword(s):  
Gas Chromatography ◽  
Alkali Metal ◽  
Absorption Spectra ◽  
Visible Radiation ◽  
Absorption Bands ◽  
Absorption Spectrophotometry ◽  
Spectrophotometric Data ◽  
Oligomeric Forms

The mechanism of controlled anionic coordination dimerization of isoprene (i.e. 2-methyl-1,3-butadiene) in the system tetrahydrofuran-isoprene-alkali metal-dialkylamine was investigated by using absorption spectrophotometry in the range of visible radiation and gas chromatography. The effect of the alkali metal (Li, Na, K) and dialkylamine (dicyclohexylamine, N-isopropylcyclohexylamine, N-methylisopropylamine) on the absorption spectra was tested. By comparing chromatographic and spectrophotometric data, the absorption bands in the range of visible radiation were identified with the existence of π-complexes between oligomeric forms of isoprene and alkali metal dialkylamide.

scholarly journals Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Wiebeler ◽  
Joachim Vollbrecht ◽  
Adam Neuba ◽  
Heinz-Siegfried Kitzerow ◽  
Stefan Schumacher
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Energy Levels ◽  
Spectroscopic Properties ◽  
Absorption Bands ◽  
Functional Theory ◽  
Vertical Excitation ◽  
Hartree Fock ◽  
Tauc Plot ◽  
Electrochemical Approach

AbstractA detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands.

The vacuum-ultraviolet absorption spectra of substituted p-benzoquinones

1989 ◽  
Vol 85 (3) ◽  
pp. 177 ◽  
Author(s):  
Paul Brint ◽  
Pericles Tsekeris ◽  
Agisilaos Bolovinos ◽  
Constantine Kosmidis
Keyword(s):  
Absorption Spectra ◽  
Vacuum Ultraviolet ◽  
Ultraviolet Absorption
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